Where's your garden?

This map created by Steve Baskauf of Vanderbilt University shows North American ecoregions as defined by the World Wildlife Fund. For a much larger, interactive version of the map see Steve's Bioimages website. For a short stack of legalese pertaining to this image, please see the bottom of this post.

IT'S A GOOD THING I'M NOT INTO CONSPIRACY THEORIES. If I were, I'd be casting a very suspicious eye on plant hardiness zones.

This concept originated with the U.S. Department of Agriculture but has become very popular in gardening circles. The idea is that plants can be assigned a numerical rating based on the minimum temperatures they are able to withstand. This gives you a rough idea of whether a given plant can survive in your garden, regardless of where the plant originated.

Imbedded in this concept is the notion that a garden can and should be free of any ties to its location. Bring in rhododendrons from China or four-o'clocks from Peru, it doesn't matter as long as the plant can survive on your site. Gardeners are even admired for their ability to grow plants from far away places. And if they are able to grow plants not rated for their zone (tropical plants in upstate New York, for example), why, they are considered positively heroic.

Now, if I were prone to believe in conspiracies, I'd say this is part of a plot cooked up by the horticulture industry to sell more plants--especially plants that are likely to struggle and die in new homes to which they are poorly suited. And then no doubt the sellers would be shocked, shocked to learn that these plants have to be replaced.

But I'd rather just propose an alternative. What if we stop admiring gardeners who pay no attention to where they live? (They can go on gardening that way if they want to. I'm suggesting that the rest of us quit just praising them for it.) Instead, let's start to admire gardeners whose work conveys a sense of place. What if, instead of worrying about plant hardiness zones, we start thinking about ecoregions instead?

I'm not sure whether anyone knows precisely where the ecoregion concept originated, but the World Wildlife Fund (aka the World Wide Fund for Nature) has done the most to define and develop it. Their less-than-wieldy definition of an ecoregion is "a large area of land or water that contains a geographically distinct assemblage of natural communities that (a) share a large majority of their species and ecological dynamics; (b) share similar environmental conditions, and; (c) interact ecologically in ways that are critical for their long-term persistence."

But you get the idea. According to the WWF, there are 825 terrestrial ecoregions on the planet, so figuring out which of them you live in can be a challenge. Fortunately, Steven Baskauf, a senior lecturer in Vanderbilt University's Department of Biological Sciences, used the WWF's GIS files to develop a map of the ecoregions in North America. I've provided a glimpse of this map above, but to see it in its full glory you have to visit Steve's Bioimages website.

There, you will most likely be able to home in on your very own region. (Currently the map represents 76 of 125 ecoregions on the continent.) For instance, I clicked on Eastern Canada and, from there, easily found that I am in the New England/Acadian Forests, known to the WWF as NA0410.

What's more, from Steve's site I was then able to link back to the National Geographic's "Ecoregion profile" of my region, which linked me to the WWF's scientific report. Back at the Bioimages site, I was also able to find a link to the WWF's list of species found in this region, as well as other images and information.

OK, "Hail to thee, NA0410" doesn't have much of a future as a bioregional anthem. But at least NA0410 is home, and the plants that come from dear old NA0410 tie me to the place I live. "Plant Hardiness Zone 5", on the other hand, is marketing. And its plants tie me to nothing except somebody's desire to make a buck.

The map shown above is copyright 2002-2004 Steve Baskauf, who used data from Olson, D. M, E. Dinerstein, E.D. Wikramanayake, N.D. Burgess, G.V.N. Powell, E.C. Underwood, J.A. D'amico, I. Itoua, H.E. Strand, J.C. Morrison, C.J. Loucks, T.F. Allnutt, T.H. Ricketts, Y. Kura, J.F. Lamoreux, W.W.Wettengel, P. Hedao, & K.R. Kassem. 2001. Terrestrial Ecoregions of the World: A New Map of Life on Earth. BioScience 51:933-938


Greg W said...

Greetings from the Wasatch and Uintas ecoregion.

I like this way of determining if a plant will grow here better than the USDA 'hardlyness' zone. I can't count the number of plants that are supposed to grow in my zone 5 that don't make it because it is too hot.

Thanks for bringing this to our attention I will be using this map from now on for all of my future plant purchases.

tina said...

Nicely said, i like shocked! how true. lol

Dee/reddirtramblings said...

A very cool idea. I've quit trying to grow stuff that doesn't like it here. It's too hard and takes the enjoyment out of it.

I'm afraid your conspiracy theory may actually be true though.~~Dee

Mary Witzl said...

What you advise here is sensible. I have always wondered about the tendency in Southern California to plant great stretches of turf in front lawns instead of succulents that do not require so much water. Grass lawns guzzle so much water, but people still plant them. Likewise, it seems a lot wiser to go with plants that are happy where we put them, not ones that are bound to fail and die miserably.

NJOrganicLawns said...

Interesting idea.

Most people just go to the local garden center around here and they generally stock what works well in the area. Pretty easy but you start seeing the same plants from house to house.

Sometimes you have to try something different.